Blade system for hammer mills



Jam 1970 s. c. JENSEN BLADE SYSTEM FOR HAMMER MILLS Filed Dec. 19, 1966 R O T N E V N SANNING C. JENSEN BYW United States Patent 3,491,959 BLADE SYSTEM FOR HAMMER MILLS Sanning C. Jensen, Jensen Mills, Neola, Iowa 51559 Filed Dec. 19, 1966, Ser. No. 612,744 Int. Cl. B02c 13/00, 13/26 US. Cl. 241-194 5 Claims ABSTRACT OF THE DISCLOSURE A hammer mill having hammers each of which are hardfaced with a hard material such as tungsten on the end but on only one of two opposite sides so that, as the load material hones the blade, the parent metal is honed away on the non-hardfaced side causing each blade to assume a shape providing much lesser kilowatt-hour consumption for greater milling efliciency.

In the prior art, the hard-faced hammers of hammer mills have been hard-faced on both sides and across the tip end. This causes a pocket to be worn in the forward side of each blade between its two hard-faced sides, with the result that such hammers have remained thick in the outer impact portion thereof and have presented to the grain a wide forward impact surface and have batted or paddled at the grain creating much resistance upon impact. This resistance has cause milling to consume greater power with inefliciency.

In summary, this invention provides blades which wear into shapes which are without the pockets described so that each blade presents sharp cutting edges on its end but on only one of its sides, the non-hard-faced side of each blade being open so as to permit the escape of grain from the non-hard-faced side of the blade, the grain being deflected by an inclined impact surface so as to be deflected to one side of the blade rather than being batted forwardly as in the prior art, each blade being honed by the load so as to have a thinner cross-section in its impact area giving lesser resistance to forward motion, the new blade system giving a hammer mill a lower kilowatt-hour power consumption that is surprisingly economical.

My new blade system further has one or more groups of hammers, the hammers of each group rotating in a same plane, one behind another, succeeding hammers of each group deflecting and diverting grain from the inclined surfaces thereof toward opposite sides of the plane in which they rotate. This is because each following blade draws the material by deflection back from the area to which a preceding blade has deflected it, with the result that the grain is retained in the area of the cutting plane until thoroughly and efficiently milled.

Other and further objects and advantages of the present invention will be apparent from the following detailed description, drawings and claims, the scope of the invention not being limited to the drawings themselves as the drawings are only for the purpose of illustrating a way in which the principles of this invention can be applied.

Other embodiments of the invention utilizing the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIGURE 1 is a side elevation of a hammer mill, with one side of the housing removed and the other part showing in section.

FIGURE 2 is a sectional view taken through the hammer mill of FIGURE 1 as it would be seen along the line 22 of FIGURE 1.

3,491,959 Patented Jan. 27, 1970 FIGURE 3 is a sectional view taken along the line 3-3 of FIGURE 1.

FIGURE 4 is a detail showing a modification of a hammer pair of this invention shown as attached to a portion of a hammer mill, the part being shown in section smilar to the showing of corresponding parts in FIG- URE 2.

Referring to FIGURE 1, a hammer mill is there generally indicated at 10, having a rotor 12 with axis 14. Two hammer carrying rods 20 are arranged on the rotor 12 and extend parallel to the axis 14.

Two hammers 40 are shown in FIGURE 1, the hammers 40 forming a hammer group generally indicated at 42. The hammers defined as a group are disposed in approximately the same plane as indicated by the dotted line 50 in FIGURE 2, the plane 50 extending at a right angle to the axis 14.

Holding means 60 in the form of approximately C- shaped resilent blade holders 62 are provided. Each blade holder 62 extends around an inner end of its respective blade and has sides 70 which are resiliently pressed toward each other, as each blade holder 62 is made of resilient material for pressing on the opposite sides of the respective blade or hammer 40 for holding the hammers 40 of a grou 42 in approximately the same plane. The sides 70 of each holder 60 have apertures therethrough receiving the respective hammer carrying rod-20.

The blades 40 of a group are arranged so as to follow one another in approximately the same swath. The blades 40 each have two sides 72 and 74, facing opposite direc tions along the axis 14, one of the sides of each of the blades is hard-faced as shown at adjacent the tip of the blade and the other side 84 of the same blade is substantially without hard facing so as to wear away in use in a manner for forming a hammer, having a forward surface which has a portion 92 which inclines from the thin forward cutting edge 94 rearwardly and to that side 84 of the blade which is disposed opposite the hardfaced side 74.

At its rearward end the inclined portion 92 terminates in a transverse portion 96 which is transversely disposed to the elongation of a cross section of a blade and also transverse to the inclined portion 92, the portion 96 extending to the side 84 of the blade.

It is most clear to realize that the blade has an inclined surface 90 which can be described as being generally inclined from the thin forward edge 94, rearwardly and to the opposite side of the blade 84 where there is no hard facing in a manner for deflecting material to the side 84 of the blade, the path of the material relative to the blade being indicated in lines at 100' in FIGURE 3.

It will be seen that the forward surface 90 inclines as seen in a horizontal cross section at a time when the blade is held vertical in the manner shown in FIGURE 3. However, when the blade is seen in side elevation in FIGURE 1, it will be seen that a cavity worn into the blade and having the surfaces 92 and 96 also has upper and lower surfaces and 112 which extend approximately horizontally as shown in FIGURE 1.

As best seen in FIGURE 2 the tip of each blade is provided with hard facing which joins the hard facing 80.

Referring to FIGURE 1, it will be seen that those blades 40 of a group follow each other sequentially past any given point in the swath thereof, and have their hardfaced sides 74 facing in opposite directions, as best seen further in FIGURE 2, and with respect to the rotor axis.

In operation this causes the deflecting surfaces or inclined surfaces 90 of the blades to a group to deflect the material being milled toward opposite sides of the plane 50, in which the blades of the group lie.

Referring to FIGURE 2, the hammer mill can have at least one other similar group of blades 152 comprising two blades 154. The blades 154 are disposed approximately in a second plane 156 which is parallel to but spaced from the first plane and from the first group of blades 42. Each blade in the first group has a blade in the second group 150 disposed approximately directly behind it when the rotor is viewed longitudinally of the axis whereby a blade of one group which is disposed adjacent a blade of another group is called one of the pair of blades 170 formed by the two blades which are adjacent each other, as seen along the axis of the rotor.

Referring to FIGURE 4, a modification is there shown in which a portion of a rotor 12 has a hammer carrying rod 210, and in which a pair of modified blades 212 have inner ends 214 provided with openings 216 therethrough, receiving the rod 210, a resilient blade holder 220 being disposed around the inner ends 214 and pressing them together, the outer ends 230* of each blade 212 being spaced apart, the inner portions 214 of the blades being closer to the rotor axis and being disposed closer together than the outer ends 230 of the blades 212, and being pressed together by the resilient blade holder 220, whereby the blades have oflYset central portions 234.

The pair 213 have their outer ends spaced apart and disposed one behind the other as seen along an axis of the rotor 12.

Each blade 212 is hard-faced on one side 240 thereof, the hard-faced side 240 being disposed on opposite sides of the respective blades 212 of the pair 213, whereby when the blades 212 become one, they deflect grain in opposite directions.

Outer end portions of the blades 212 have those sides 242 thereof which are opposite their hard-faced sides 240, substantially free of hard facing for introducing the wear characteristics above described with respect to the pair of blades 170 in FIGURE 2.

Hard facing 250, therefore, extends along the sides 240 and across the outer ends of each blade 212.

In the use of the blade modification of FIGURE 4, it is to be understood that the blades 212 of a pair directly substituted for the blades 170 of a pair in FIGURE 2, in the sense that blades grouped with the blades 212 on the same rotor respectively, are arranged to have the same cooperative effect with other blades in the same group, which is the case with the modification of FIGURE 2.

More particularly, and as best seen in FIGURE 2, a blade 40 of a group 42 directs grain to one side of the swath, whereas the blade 40 which follows it, in the same group, directs grain toward the other side of the swath by the deflecting action above mentioned. For this reason, the material is maintained in the area of the cutting blades, whereas otherwise all blades might direct the material to a side of the cutting blade area with loss of efliciency.

It can seem to an observer that it might be desirable not to have hard facing at 120 on the end of a blade but the hard facing 120 at the end is very important, because it provides a cutting edge at the very tip where cutting is the most effective.

In addition hard facing across the outerend tends to cause the base metal of the hammer, called the parent metal, to be honed away in a certain configuration, as best seen in FIGURE 1, in which the upper wall 110 of the groove 90 inclines inwardly towards the rotor axis 14 as the rearward edge 300 is approached. This inclination of the wall 110 tends to draw material inwardly from the outer wall 330 of the housing where it becomes properly milled, instead of being missed, which latter can happen when grain lies in the area between the blade and the housing 330.

Having the hard facing 120 across the end of the blade further tends to cause the parent metal of the blade not to be worn away at the tip as fast. This is very important because the parent metal Wears away quickly, then the hard faced side will also wear away faster until it is rounded 01f on the forward side on the outer end, the wearing continuing until the hammer is not as long, whereby the shorter hammer misses material between the hammer and the wall 330.

It will be seen from FIGURES 1 and 2 that those areas of the hammer mill which are disposed alongside the nonhard-faced sides of the blades are sutficiently unobstructed as to substantially allow material deflected by the nonhard-faced sides of the blades to move with respect to a respective rotating blade continuously in a direction partially rearwardly of the direction of travel of each blade so as to freely escape from alongside the non-hard-faced side of the tip of each blade.

As thus described this invention is believed to fulfill the objects above set forth for providing a superior blade system for hammer mills.

From the foregoing description, it is thought to be obvious that a blade system for ham'mer mills constructed in accordance with my invention is particularly well adapted for use, by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that my invention can be changed and modified without departing from the principles and spirit thereof, and for this reason, I do not wish to be understood as limiting myself to the precise arrangement and formation of the several parts herein shown in carrying out my invention in practice, except as claimed.

I claim:

1. A hammer mill having: a rotor having an axis, a blade-carrying rod means arranged on said rator in parallelism with said axis, a plurality of hammer blades in said hammer mill, said blades each having two sides facing opposite directions along said rotor axis, one of the terminal sides of each of said blades being hard-faced adjacent the tip of the blade, the other terminal side of the same blade being substantially without hard-facing so as to wear away in use in a manner for forming a blade having a forward surface which generally inclines, forming thinner forward portions at the end of the blade on the hard-faced side of the blade to gradually thickening portions of the blade as the rearward and non-hard-faced side of the blades is approached so that a deflecting surface is caused to exist on the blade which is adapted to deflect material being milled in a direction toward the said approximately non-hard-faced side of said blade, those areas of said hammer mill which are disposed alongside the non-hard-faced sides of said blades being sufiiciently unobstructed as to substantially allow material deflected by the non-hard-faced sides of said blades to move with respect to a respective rotating 'blade continuously in a direction partially rearwardly of the direction of travel of that blade so as to freely escape from alongside the non-hard-faced side of the tip of that blade.

2. The hammer mill of claim 1 further comprising: at least two of said hammers forming a hammer group, the ham mers in said group being disposed approximately in a same plane extending at a right angle to said axis, means on said rod means and cooperative with said rotor for holding the hammers of said group in said approximate same plane, the blades of a group being arranged so as to follow one another in approximately the same swath,

those blades of said group which are adjacent each other having their hard-faced sides facing in opposite directions with respect to rotor axis, whereby the inclined deflecting surfaces of said blades in use will deflect material being milled toward opposite sides of the plane of the blades of the group.

3. The combination of claim 2 in which the said hammer mill has at least one other similar group of blades (152) secured thereto in a similar manner, the said similar group (152) of blades having their outer ends disposed approximately in a second plane parallel to, but spaced from the first-mentioned group of blades (42) to permit material being milled to pass there-between so that said blades tend to cut the grain with a minimum of power wasted causing the grain to shift.

4. The combination of claim 2 in which the said hammer mill has at least one other similar group of blades (152) secured thereto in a similar manner, the said similar group (152) of blades having their outer ends disposed approximately in a second plane parallel to, but spaced from the first-mentioned group of blades (42) to permit material being milled to pass therebetween so that said blades tend to cut the grain with a minimum of power wasted causing the grain to shift, a blade (212) in one of said groups being disposed alongside a blade (212) of the other of said groups as seen along said axis for defining a pair of (213) of blades, outer ends of the blades of a pair being spaced apart, inner portions closer to said axis of the blades of a pair being disposed closer together than the outer ends of the blades of a pair, the said inner ends of the blades of a pair being disposed close enough together as compared with the outer ends that the shapes of the blades of a pair as thus defined substantially help to make it possible for the shapes of said blades to substantially assist in maintaining the outer blades of the ends of a pair at a greater spacing along said axis than the inner ends of said pair.

5. The combination of claim 2 in which the said hammer mill has at least one other similar group of blades (152) secured thereto in a similar manner, the said similar group (152) of blades having their outer ends disposed approximately in a second plane parallel to, but spaced from the first-mentioned group of blades (42) to perimt material being milled to pass therebetween so that said blades tend to cut the grain with a minimum of power wasted causing the grain to shift, a blade (212) in one of said groups being disposed alongside a blade (212) of the other of said groups as seen along said axis for defining a pair (213) of blades, outer ends of the blades of a pair being spaced apart, inner portions closer to said axis of the blades of a pair being disposed closer together than the outer ends of the blades of a pair, the said inner ends of the blades of a pair being disposed close enough together as compared with the outer ends that the shapes of the blades of a pair as thus defined substantially help to make it possible for the shapes of said blades to substantially assist in maintaining the outer blades of the ends of a pair at a greater spacing along said axis than the inner ends of said pair, a same approximately C-shaped resilient blade holder element extending around the inner ends of the blades of a pair and pressing them toward each other.

References Cited UNITED STATES PATENTS 2,237,510 4/1941 Tankersley 241 2,763,439 9/1956 Mankofi 241-197 2,810,529 10/1957 Jensen 241194 2,922,589 1/1960 Sheldon 24l197 X 3,015,452 1/1962 Jensen 24l-194 ROBERT C. RIORDON, Primary Examiner M. G. RASKIN, Assistant Examiner US. Cl, X,R. 

